Oi Chums,
An official street by street map of the Seattle Metroplex would be AWESOME, but hard to make no doubt. And if it did not mesh with your vision of what certain areas of the city looked like well then you would be making it up any way. It is likeley that if we ever did get a street by street of Seatte thats all we would get and I run games that cover the Globe.
Personaly, I use Google Earth. You can take an adddress from a sourcebook, like Seattle 2072, and search for it. Plop down a marker add what fluff and crunch you want for that locale and whammo. Then use the street Cam Veiw to give you more detail. We even use the ruler tool to help with distances in combat scenes. You can create overlays to mark out Gang territory, create borders to map out city sectors and you have every city in the world at your fingertips. On game day I set up in the living room connecting my laptop to my Big Screen and show the players what I want on the screen. I can hide stuff I don't want them to see exposing it as they do their legwork across the city. Is a great tool. Check it out.